This is possible mistaken reporting. There have been reporting of ash clouds or steam clouds off the coast during the evening of 7-August-2021. This would be in the volcano system Krýsuvík-Trölladyngja.
The ash cloud or steam cloud would indicate an activity off the coastline or possible eruption activity in the ocean. Explosive events like that appear a lot more clearly as harmonic tremor on SIL stations and according to news reports nothing has been seen so far in the harmonic tremor data. There have been no earthquake activity in the area where the clouds are supposed to have been seen.
The coast guard has been sent to this area, as they where nearby anyway. I don’t know if anything has been reported so far. The weather is fine in south Iceland and I don’t think there is a lot of ocean waves, but as this is the Atlantic ocean there can be ocean waves even if there is no wind, since the ocean waves can arrive from parts of the ocean with bad weather thousands of kilometres away.
If anything new is reported I am going to update this article or write a new one.
Coast Guard is saying that the report from Selvogsviti might have been someone seeing steam clouds from Gunnuhver but that doesn’t seem to make a lot of sense to me considering how far apart they are.
The problem is that nobody took a picture of this cloud and almost everyone has a picture phone today. There is a high risk of an eruption in the ocean now, so far that has not yet happened.
This fella on the video here said something about boulders rising in the sea. Pumice? He doesn’t mention ash/steam clouds. The naval vessel “Thor” was dispatched to investigate.
https://www.youtube.com/watch?v=KDjLJRBe6R8
Eruption rather vigorous today. Over-topping the southern crater wall. Could be another flow direction change if it’s compromised. Looks like when this started, an area was already breached, allowing some lava to flow in the old outlet area.
Considering how much lava has built up to the east so far, it seems logical that there could be a change in direction of the lava. It would not surprise me if some began to flow west into the northern part of Geldingadalir again or to the south. Since Geldingadalir is now full of lava, it would not take long for it to travel out of the valley if it does that. One thing to keep in mind is that basalt shrinks a lot as it cools any new flow will first fill cracks and holes opened by the lava shrinking in the previous areas which might slow it down a little bit.